Generalized decrease in brain glucose metabolism during fasting in humans studied by PET

1989 ◽  
Vol 256 (6) ◽  
pp. E805-E810 ◽  
Author(s):  
C. Redies ◽  
L. J. Hoffer ◽  
C. Beil ◽  
E. B. Marliss ◽  
A. C. Evans ◽  
...  
Keyword(s):  
Blood Flow ◽  
Blood Volume ◽  
Ketone Bodies ◽  
Oxygen Metabolism ◽  
Whole Body ◽  
Transfer Coefficients ◽  
Oxygen Utilization ◽  
Whole Brain ◽  
Brain Glucose ◽  
The Brain

In prolonged fasting, the brain derives a large portion of its oxidative energy from the ketone bodies, beta-hydroxybutyrate and acetoacetate, thereby reducing whole body glucose consumption. Energy substrate utilization differs regionally in the brain of fasting rat, but comparable information has hitherto been unavailable in humans. We used positron emission tomography (PET) to study regional brain glucose and oxygen metabolism, blood flow, and blood volume in four obese subjects before and after a 3-wk total fast. Whole brain glucose utilization fell to 54% of control (postabsorptive) values (P less than 0.002). The whole brain rate constant for glucose tracer phosphorylation fell to 51% of control values (P less than 0.002). Both parameters decreased uniformly throughout the brain. The 2-fluoro-2-deoxy-D-glucose lumped constant decreased from a control value of 0.57 to 0.43 (P less than 0.01). Regional blood-brain barrier transfer coefficients for glucose tracer, regional oxygen utilization, blood flow, and blood volume were unchanged.

Changes in cerebral blood flow and carbohydrate metabolism during acute hyperketonemia

1996 ◽  
Vol 270 (5) ◽  
pp. E746-E751 ◽  
Author(s):  
S. G. Hasselbalch ◽  
P. L. Madsen ◽  
L. P. Hageman ◽  
K. S. Olsen ◽  
N. Justesen ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Glucose Metabolism ◽  
Carbohydrate Metabolism ◽  
Ketone Bodies ◽  
Regional Analysis ◽  
Oxygen Metabolism ◽  
Blood Concentrations ◽  
Positron Emission ◽  
The Brain

During starvation, brain energy metabolism in humans changes toward oxidation of ketone bodies. To investigate if this shift is directly coupled to circulating blood concentrations of ketone bodies, we measured global cerebral blood flow (CBF) and global cerebral carbohydrate metabolism with the Kety-Schmidt technique before and during intravenous infusion with ketone bodies. During acute hyperketonemia (mean beta-hydroxybutyrate blood concentration 2.16 mM), cerebral uptake of ketones increased from 1.11 to 5.60 mumol.100 g-1.min-1, counterbalanced by an equivalent reduction of the cerebral glucose metabolism from 25.8 to 17.2 mumol.100 g-1.min-1, with the net result being an unchanged cerebral uptake of carbohydrates. In accordance with this, global cerebral oxygen metabolism was not significantly altered (144 vs. 135 mumol.100 g-1.min-1). The unchanged global cerebral metabolic activity was accompanied by a 39% increase in CBF from 51.0 to 70.9 ml.100 g-1.min-1. Regional analysis of the glucose metabolism by positron emission tomography-[18F]fluoro-2-deoxy-D-glucose indicated that mesencephalon does not oxidize ketone bodies to the same extent as the rest of the brain. It was concluded that the immediate oxidation of ketone bodies induced a decrease in cerebral glucose uptake in spite of an adequate glucose supply to the brain. Furthermore, acute hyperketonemia caused a resetting of the coupling between CBF and metabolism that could not be explained by alterations in arterial CO2 tension or pH.

Effects of subarachnoid hemorrhage on cerebral blood volume, blood flow, and oxygen utilization in humans

1977 ◽  
Vol 46 (4) ◽  
pp. 446-453 ◽  
Author(s):  
Robert L. Grubb ◽  
Marcus E. Raichle ◽  
John O. Eichling ◽  
Mokhtar H. Gado
Keyword(s):  
Blood Flow ◽  
Subarachnoid Hemorrhage ◽  
Blood Volume ◽  
Cerebral Vasospasm ◽  
Cerebral Blood Volume ◽  
Neurological Deficits ◽  
Regional Cerebral Blood ◽  
Oxygen Utilization ◽  
Ruptured Intracranial Aneurysm ◽  
Regional Cerebral Blood Volume

✓ Forty-five studies of regional cerebral blood volume (rCBV), regional cerebral blood flow (rCBF), and regional cerebral oxygen utilization (rCMRO2) were performed in 30 patients undergoing diagnostic cerebral angiography for evaluation of a subarachnoid hemorrhage due to a ruptured intracranial aneurysm. Tracer methods employing radioactive oxygen-15 were used to measure rCBV, rCBF, and rCMRO2. The patient studies were divided into groups based on their neurological status and the presence or absence of cerebral vasospasm. Subarachnoid hemorrhage, with and without vasospasm, produced significant decreases in CBF and CMRO2. In general, patients with more severe neurological deficits, and patients with more severe degrees of vasospasm, had a more marked depression of CBF and CMRO2. The most striking finding was a significant (p < 0.001) increase in CBV (to 58% above normal) in patients with severe neurological deficits associated with severe cerebral vasospasm. This large increase suggests that cerebral vasospasm consists of constriction of the large, radiographically visible extraparenchymal vessels accompanied by a massive dilation of intraparenchymal vessels.

Global cerebral blood flow, blood volume, and oxygen metabolism in patients with migraine headache

Neurology ◽  
1998 ◽  
Vol 50 (6) ◽  
pp. 1736-1740 ◽  
Author(s):  
E. M. Bednarczyk ◽  
B. Remler ◽  
C. Weikart ◽  
A. D. Nelson ◽  
R. C. Reed
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Blood Volume ◽  
Migraine Headache ◽  
Oxygen Metabolism ◽  
Global Cerebral Blood Flow

scholarly journals PET studies of changes in cerebral blood flow and oxygen metabolism after unilateral microembolization of the brain in anesthetized dogs.

Stroke ◽  
1987 ◽  
Vol 18 (1) ◽  
pp. 128-137 ◽  
Author(s):  
J Weyne ◽  
G De Ley ◽  
G Demeester ◽  
C Vandecasteele ◽  
F L Vermeulen ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Oxygen Metabolism ◽  
Anesthetized Dogs ◽  
The Brain

Ketogenic Diet, Aging, and Neurodegeneration

2016 ◽  
Author(s):  
Kui Xu ◽  
Joseph C. LaManna ◽  
Michelle A. Puchowicz
Keyword(s):  
Oxidative Stress ◽  
Energy Source ◽  
Blood Flow ◽  
Ketogenic Diet ◽  
Ketone Bodies ◽  
Neurovascular Unit ◽  
Cerebral Metabolic Rate ◽  
Downstream Effects ◽  
Atp Supply ◽  
The Brain

The brain is normally completely dependent on glucose, but is capable of using ketones as an alternate energy source, as occurs with prolonged starvation or chronic feeding of a ketogenic diet. Research has shown that ketosis is neuroprotective against ischemic insults in rodents. This review focuses on investigating the mechanistic links to neuroprotection by ketosis in the aged. Recovery from stroke and other pathophysiological conditions in the aged is challenging. Cerebral metabolic rate for glucose, cerebral blood flow, and the defenses against oxidative stress are known to decline with age, suggesting dysfunction of the neurovascular unit. One mechanism of neuroprotection by ketosis involves succinate-induced stabilization of hypoxic inducible factor-1alpha (HIF1α‎) and its downstream effects on intermediary metabolism. The chapter hypothesizes that ketone bodies play a role in the restoration of energy balance (stabilization of ATP supply) and act as signaling molecules through the up-regulation of salvation pathways targeted by HIF1α‎.

Cerebral blood flow, oxygen utilization, and blood volume in dementia

Neurology ◽  
1977 ◽  
Vol 27 (10) ◽  
pp. 905-905 ◽  
Author(s):  
R. L. GRUBB ◽  
M. E. RAICHLE ◽  
M. H. GADO ◽  
J. O. EICHLING ◽  
C. P. HUGHES
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Blood Volume ◽  
Oxygen Utilization

scholarly journals Regional Brain Blood Flow, Blood Volume, and Haematocrit Values in the Adult Rat

1983 ◽  
Vol 3 (2) ◽  
pp. 254-256 ◽  
Author(s):  
Jill E. Cremer ◽  
Malcolm P. Seville
Keyword(s):  
Blood Flow ◽  
Blood Volume ◽  
Brain Regions ◽  
Adult Rats ◽  
Adult Rat ◽  
Systemic Artery ◽  
Significant Difference ◽  
Total Body ◽  
The Brain ◽  
Made In

Measurements of red cell volume, plasma volume, and tissue haematocrit (Hct) were made in 14 brain regions in adult rats using 51Cr-tagged red cells and 125I-labeled human serum albumin. The mean large vessel (systemic artery) Hct was 41.8, total body Hct was 35.3, and of the brain regions, the lowest value (septal nucleus) was 25.91 and the highest (visual cortex) was 32.05. The lowest blood volume was 6.29 μl g−1 (caudate putamen) and the highest was 14.44 μl g−1 (inferior colliculus). There was a significant difference between regions in both blood volume and tissue blood Hct. When brain regions were ranked in order of blood volume, this did not coincide with the order for blood flow.

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